The present invention relates to a new system and method for assisting the start of an electrically powered vehicle. More particularly, the invention relates to a system and method configured to obtain the insulation resistance value of the vehicle battery.
Improving safety and comfort is always a concern in the automotive industry. For electrically powered vehicles, such as electric or hybrid powered vehicles, insulation of the high voltage battery is of significant importance to guarantee safety of the entire vehicle and its occupants. For that, electrically powered vehicles demand applications that check whether the insulation level of the battery is adequate or not before performing specific tasks, such as starting the vehicle.
The start of an electrically powered vehicle is a potentially dangerous task and could pose a risk for the occupants, or even the vehicle itself, if the battery is poorly insulated.
For that, before enabling the start of the vehicle, the resistance between the high voltage lines and chassis must be measured. From this measurement, the insulation level of the battery can be determined and starting can be enabled or disabled in consequence.
Currently, there exist commercial sensors capable of providing this measurement. However, on average, sensors of this kind usually require about 2 seconds to obtain a rough measurement and about 20 seconds to obtain a definite value. The 2-second time measurement just provides an indication in the event of very serious isolation fault. Thus, in order to ensure safety in the use of electric vehicles, a driver has to wait a considerable time before the vehicle actually starts. This time corresponds with the time needed by the sensor to obtain the definite insulation resistance value.
This starting delay reduces driving comfort.
Therefore, it would be desirable in the electrically powered vehicle industry to develop an improved system and method that are capable of reducing this vehicle starting delay while ensuring safety of such start.